1. Field of the Invention
The present invention relates to controllers for inverters and more particularly to a controller for an inverter provided with fail-safe means at the time of a detected failure.
2. Background Art
For a controller for an inverter (hereinafter this may be called an inverter controller also), it is necessary to improve the reliability of a system. Particularly, in the case of a cooperation control system including a plurality of processing units, a fail-safe function at the time of a failure detected in a processing unit, for example, is important.
In order to improve the reliability of the system, JP Patent Publication (Kokai) No. 10-289001 A (1998) discloses a control system as a redundant system including a main controller and a sub-controller therein. The provision of the sub-controller improves the reliability of the system when something abnormal occurs in the main controller.